1. Technical Field
The present invention relates generally to tools and instruments and more particularly to a tool for restricting the maximum opening of a throttle valve by limiting the amount by which an accelerator pedal lever may be actuated.
2. Discussion
During the preproduction development of a vehicle, it is frequently necessary to conduct tests on the vehicle wherein the engine is operated at a specific throttle position or up to a predetermined maximum throttle position. These tests are commonly employed to either compare the designs of several components and evaluate their performance, obtain data on a particular vehicle configuration which would be used for software programming or the design of other components, or to identify the cause of a problem and aid in its resolution. As many of the variables that are quantified during these tests are the resultant of the configuration of the vehicle as a whole, it is often desirable to perform these tests by driving the vehicle on a road surface, using a device to limit the maximum throttle valve position.
Similarly, when servicing a vehicle it is frequently required to diagnose engine problems or tune the operation of the engine by conduct a test wherein the engine throttle valve is operated at a specific throttle position or up to a predetermined maximum throttle position. As with the preproduction development testing, it is desirable to perform these tests using a device which will limit the throttle valve position.
It has been a common practice to employ a stop-block when conducting such tests to limit the amount range of the throttle valve to a desired maximum position. Stop-blocks are solid items which are loosely placed under the accelerator pedal; contact between the stop-block and the accelerator pedal effectively prevents the further opening of the throttle valve. While stop-blocks have proven to be somewhat effective, their use is accompanied by several substantial drawbacks.
For example, it is often difficult to obtain repeatable results when using stop-blocks, even where the same stop-block and vehicle are being used in a test. This is due to the common use of a pivot point where the accelerator pedal is connected to the accelerator pedal lever. As such, the maximum throttle valve position is influenced to a degree by the angle at which the pedal is made to contact the stop-block. The errors associated with this phenomena are dependant upon the design of the accelerator pedal and pedal lever, but become most significant when the tests are being performed by several technicians or where the accelerator pedal is operated in an unconventional manner (e.g., technician servicing the vehicle operates accelerator without being seated in the driver's seat).
Another drawback concerns the adjustment of the stop-block to "fine-tune" the maximum opening of the throttle valve. As the outcome depends not only on the overall height of the stop-block but also the relative position of the contact point between the stop-block and the accelerator pedal, efforts to fine-tune a maximum setting were largely a matter of trial-and-error and therefore, time consuming. As a result, the process of fine-tuning was a tedious and time-consuming ordeal.
The problems with stop-blocks are compounded when the tests were performed on a range of vehicles, such as when base-lining the performance of or servicing several vehicle models. The variability in the configuration of the vehicle models often required the use of many different stop-blocks, due not only to differences in the mechanical configuration of the accelerator pedal and pedal link, but also the configuration of the interior (e.g., flooring type, design of the floor pan). As such, a new stop-block was often required for every vehicle model that was tested.
Therefore, in view of these drawbacks, there remains a need in the art for an inexpensive, easily adjusted throttle stop tool which is readily adaptable to a wide range of vehicle designs and provides accurate and repeatable results.